Disclosed herein is a curable sublimation ink and a transfer printing method comprising applying a curable sublimation ink comprising at least one curable component and at least one sublimation colorant in a desired pattern onto a transfer substrate to form an image on the transfer substrate at a first temperature which is below a sublimation temperature of the sublimation colorant; curing the image on the transfer substrate; and optionally, bringing the transfer substrate into contact with a final image-receiving substrate and heating to a second temperature which is sufficient to cause the sublimation colorant to sublime and form a permanent image on the final image-receiving substrate.
Transfer printing processes and materials are in great demand. The imaging of textiles and other substrates using thermal transfer of sublimation dyes has been commercially practiced for more than 50 years. Transfer printing generally comprises preparing a transfer sheet or substrate bearing the image to be transferred, and subsequently transferring the image from the transfer sheet or substrate to a permanent substrate upon which the image is to permanently appear. The original printers for sublimation printing processes employed electrostatic printing technology using toners and marking materials. More recently, sublimation printing processes employ large format ink jet printers using specially formulated inks.
Generally, a sublimation dye process consists of two steps. In a first step, an ink or a toner containing a sublimation dye creates an image on a transfer sheet. In a second step, heating transfers the image to a permanent substrate. With heating, the sublimation dye vaporizes and is transferred onto the final substrate. Current sublimation dye processes can have disadvantages. For example, sublimation inks can require an organic solvent which needs to be evaporated. Sublimation toners can offset onto the permanent substrate or require excessive heating. For both ink and toner, the sublimation processes can be high energy processes.
Ink jet ink sublimation transfer printing typically employs sublimation dye inks comprising a pigment suspended in a liquid solvent such as water. The transfer printing process generally comprises two processes: a first transfer process wherein images are initially printed on an intermediate, such as coated transfer paper, as a reverse image of the final design; and a second transfer process wherein the reverse image is transferred from the transfer paper onto a final substrate, such as polyester fabric, typically using a heat press operating at an elevated temperature, such as from about 180° C. to about 210° C. Under high temperature and pressure, the dye turns into a gas, permeates the fabric, and then solidifies into its fibers. The fabric is permanently dyed with the final image and can be washed without damaging the quality of the image.
Traditional ink jet sublimation transfer inks are water based systems. Unlike traditional water-soluble ink jet inks containing dyes, sublimation transfer ink jet ink including a sublimation dye tends to cause clogging believed due to the generation of precipitates (aggregates), degradation of dispersion stability, and/or evaporation of moisture from the nozzles. In particular, when the printing apparatus is not operated for a long time, clogging is likely to occur due to evaporation of moisture. To address this issue, a humectant can be added to suppress the evaporation of moisture. However, the sublimation transfer method requires heating for a predetermined time at temperatures higher than the sublimation point of the sublimation dye. Therefore, even if a high-boiling organic solvent is used as a humectant, the solvent is evaporated at the heating temperature during sublimation transfer, resulting in environmental pollution.
Sublimation dye has been used in xerographic technology. Most color toner systems currently in use are formulated with low melt viscosity resin which can make the toner too tacky and sticky for use in sublimation dye transfer sheets which are used at elevated temperatures. These toner systems can prevent clean transfer of the dye alone (that is, free of unwanted resin transfer). Toners employing high molecular weight polymer resin have been proposed as an alternative to low molecular weight linear polymer resins, wherein the high molecular weight resin is from about 75,000 to about 300,000 and preferably above about 300,000 and where the Tg of the binder resin is at least about 160° C. However, the high molecular weight and high Tg polymer can require a very high temperature during the first fixing stage which is not an environmentally advantageous procedure and further can cause pre-sublimation of the dye.
U.S. Pat. No. 7,237,886, which is hereby incorporated by reference herein in its entirety, describes, in the Abstract thereof, an ink for sublimation transfer ink jet recording including water, at least one sugar alcohol containing not less than four OH groups, a sublimation dye, and a dispersant. The ink is printed on a sheet medium by ink jet printing, and then the sheet medium is heated to sublimate and transfer the sublimation dye onto an object to be dyed. The ink for ink jet recording and the sublimation transfer dyeing method using the ink not only can maintain performances such as storage stability and high-quality recording images, but also can reduce environmental pollution, effectively prevent nozzle clogging, and exhibit good dispersion stability. See also, U.S. Pat. No. 6,713,222, which is hereby incorporated by reference herein in its entirety.
Thermal transfer sublimation dyes have been incorporated into toners for sublimation transfer processes using laser printers for use, for example, with personal computers.
U.S. Pat. No. 6,270,933, which is hereby incorporated by reference herein in its entirety, describes, in the Abstract thereof, a commercially useful color thermal transfer dye sublimation toner comprising at least a binder resin and a sublimation dye component, the binder resin comprising a high molecular weight polymer having a molecular weight of about 75,000, and a temperature, T1, of at least about 160° C., at which the viscosity is equal to 1×103, and the sublimation dye comprising a dye which sublimes at elevated temperatures above about 100° C. The invention further defines a process for the use of the toner.
U.S. Pat. No. 6,270,933, which is hereby incorporated by reference herein in its entirety, describes, in the Abstract thereof, a process for crosslinking an image comprising applying ultraviolet light to an image comprised of a toner containing an unsaturated resin and colorant.
U.S. Pat. No. 5,366,836, which is hereby incorporated by reference herein in its entirety, describes, in the Abstract thereof, a process for forming color xerographic images by using a toner which comprises one or more dyes. Also disclosed is a process for making a toner which comprises one or more dyes.
U.S. Patent Publication 2006/0100300, U.S. Ser. No. 10/981,528, which is hereby incorporated by reference herein in its entirety, describes, in the Abstract thereof, a composition including an unsaturated sulfopolyester amine resin, and processes for preparing and using thereof.
U.S. Pat. No. 7,479,307, which is hereby incorporated by reference herein in its entirety, describes, in the Abstract thereof, toner compositions comprised of a polymer, an optional colorant, and an UV light curable oligomer. Also disclosed are methods for producing a UV curable toner composition, the toner compositions produced thereby, and methods of utilizing the UV curable toner compositions in various painting applications.
U.S. Pat. No. 6,713,222, which is hereby incorporated by reference herein in its entirety, describes, in the Abstract thereof, a process for crosslinking an image comprising applying ultraviolet light to an image comprised of a toner containing an unsaturated resin and colorant.
U.S. Pat. No. 6,713,222, which is hereby incorporated by reference herein in its entirety, describes, in the Abstract thereof, an ink-jet ink composition suitable for use in secondary transfer processes wherein the ink-jet ink composition contains a pre-dispersion containing at least a sublimation colorant combined with an ink-jet ink containing at least a non-sublimable colorant. Upon printing, a monochrome substrate, a multi-color image can be transferred to a permanent substrate with the application of heat and pressure. The monochrome intermediate transfer image is created by the non-sublimable colorant upon printing. The multi-color permanent image is generated as elevated temperatures and pressure of the transfer process cause the sublimation colorant to sublime and bond to the permanent substrate.
Currently available materials and processes for sublimation transfer are suitable for their intended purposes. However, a need remains for improved materials and methods for sublimation transfer applications. Specifically, a need remains for improved sublimation transfer materials and processes that are free of the potential adverse effect of oxidation-reduction on the sublimation dye as can be found with non-solvent humectants (sugar alcohol) in water based inks. Further, a need remains for improved sublimation transfer materials and processes that are green, for example, that do not require a high temperature in the fixing stage, and that do not cause the sublimation dye to pre-sublimate in the fixing stage.
The appropriate components and process aspects of the each of the foregoing U.S. Patents and Patent Publications may be selected for the present disclosure in embodiments thereof. Further, throughout this application, various publications, patents, and published patent applications are referred to by an identifying citation. The disclosures of the publications, patents, and published patent applications referenced in this application are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this invention pertains.